/*
 * QObject JSON integration
 *
 * Copyright IBM, Corp. 2009
 * Copyright 2016 - Cyberhaven
 *
 * Authors:
 *  Anthony Liguori   <aliguori@us.ibm.com>
 *  Vitaly Chipounov  <vitaly@cyberhaven.io>
 *
 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
 * See the COPYING.LIB file in the top-level directory.
 *
 */

#include <inttypes.h>
#include <stdio.h>
#include <string.h>

#include "json-lexer.h"
#include "json-parser.h"
#include "json-streamer.h"
#include "q.h"
#include "qbool.h"
#include "qdict.h"
#include "qfloat.h"
#include "qint.h"
#include "qjson.h"
#include "qlist.h"

typedef struct JSONParsingState {
    JSONMessageParser parser;
    va_list *ap;
    QObject *result;
} JSONParsingState;

static void parse_json(JSONMessageParser *parser, QList *tokens) {
    JSONParsingState *s = container_of(parser, JSONParsingState, parser);
    s->result = json_parser_parse(tokens, s->ap);
}

QObject *qobject_from_jsonv(const char *string, va_list *ap) {
    JSONParsingState state = {};

    state.ap = ap;

    json_message_parser_init(&state.parser, parse_json);
    json_message_parser_feed(&state.parser, string, strlen(string));
    json_message_parser_flush(&state.parser);
    json_message_parser_destroy(&state.parser);

    return state.result;
}

QObject *qobject_from_json(const char *string) {
    return qobject_from_jsonv(string, NULL);
}

/*
 * IMPORTANT: This function aborts on error, thus it must not
 * be used with untrusted arguments.
 */
QObject *qobject_from_jsonf(const char *string, ...) {
    QObject *obj;
    va_list ap;

    va_start(ap, string);
    obj = qobject_from_jsonv(string, &ap);
    va_end(ap);

    assert(obj != NULL);
    return obj;
}

typedef struct ToJsonIterState {
    int indent;
    int pretty;
    int count;
    QString *str;
} ToJsonIterState;

static void to_json(const QObject *obj, QString *str, int pretty, int indent);

static void to_json_dict_iter(const char *key, QObject *obj, void *opaque) {
    ToJsonIterState *s = opaque;
    QString *qkey;
    int j;

    if (s->count)
        qstring_append(s->str, ", ");

    if (s->pretty) {
        qstring_append(s->str, "\n");
        for (j = 0; j < s->indent; j++)
            qstring_append(s->str, "    ");
    }

    qkey = qstring_from_str(key);
    to_json(QOBJECT(qkey), s->str, s->pretty, s->indent);
    QDECREF(qkey);

    qstring_append(s->str, ": ");
    to_json(obj, s->str, s->pretty, s->indent);
    s->count++;
}

static void to_json_list_iter(QObject *obj, void *opaque) {
    ToJsonIterState *s = opaque;
    int j;

    if (s->count)
        qstring_append(s->str, ", ");

    if (s->pretty) {
        qstring_append(s->str, "\n");
        for (j = 0; j < s->indent; j++)
            qstring_append(s->str, "    ");
    }

    to_json(obj, s->str, s->pretty, s->indent);
    s->count++;
}

static void to_json(const QObject *obj, QString *str, int pretty, int indent) {
    switch (qobject_type(obj)) {
        case QTYPE_QINT: {
            QInt *val = qobject_to_qint(obj);
            char buffer[1024];

            snprintf(buffer, sizeof(buffer), "%" PRId64, qint_get_int(val));
            qstring_append(str, buffer);
            break;
        }
        case QTYPE_QSTRING: {
            QString *val = qobject_to_qstring(obj);
            const char *ptr;

            ptr = qstring_get_str(val);
            qstring_append(str, "\"");
            while (*ptr) {
                if ((ptr[0] & 0xE0) == 0xE0 && (ptr[1] & 0x80) && (ptr[2] & 0x80)) {
                    uint16_t wchar;
                    char escape[7];

                    wchar = (ptr[0] & 0x0F) << 12;
                    wchar |= (ptr[1] & 0x3F) << 6;
                    wchar |= (ptr[2] & 0x3F);
                    ptr += 2;

                    snprintf(escape, sizeof(escape), "\\u%04X", wchar);
                    qstring_append(str, escape);
                } else if ((ptr[0] & 0xE0) == 0xC0 && (ptr[1] & 0x80)) {
                    uint16_t wchar;
                    char escape[7];

                    wchar = (ptr[0] & 0x1F) << 6;
                    wchar |= (ptr[1] & 0x3F);
                    ptr++;

                    snprintf(escape, sizeof(escape), "\\u%04X", wchar);
                    qstring_append(str, escape);
                } else
                    switch (ptr[0]) {
                        case '\"':
                            qstring_append(str, "\\\"");
                            break;
                        case '\\':
                            qstring_append(str, "\\\\");
                            break;
                        case '\b':
                            qstring_append(str, "\\b");
                            break;
                        case '\f':
                            qstring_append(str, "\\f");
                            break;
                        case '\n':
                            qstring_append(str, "\\n");
                            break;
                        case '\r':
                            qstring_append(str, "\\r");
                            break;
                        case '\t':
                            qstring_append(str, "\\t");
                            break;
                        default: {
                            if (ptr[0] <= 0x1F) {
                                char escape[7];
                                snprintf(escape, sizeof(escape), "\\u%04X", ptr[0]);
                                qstring_append(str, escape);
                            } else {
                                char buf[2] = {ptr[0], 0};
                                qstring_append(str, buf);
                            }
                            break;
                        }
                    }
                ptr++;
            }
            qstring_append(str, "\"");
            break;
        }
        case QTYPE_QDICT: {
            ToJsonIterState s;
            QDict *val = qobject_to_qdict(obj);

            s.count = 0;
            s.str = str;
            s.indent = indent + 1;
            s.pretty = pretty;
            qstring_append(str, "{");
            qdict_iter(val, to_json_dict_iter, &s);
            if (pretty) {
                int j;
                qstring_append(str, "\n");
                for (j = 0; j < indent; j++)
                    qstring_append(str, "    ");
            }
            qstring_append(str, "}");
            break;
        }
        case QTYPE_QLIST: {
            ToJsonIterState s;
            QList *val = qobject_to_qlist(obj);

            s.count = 0;
            s.str = str;
            s.indent = indent + 1;
            s.pretty = pretty;
            qstring_append(str, "[");
            qlist_iter(val, (void *) to_json_list_iter, &s);
            if (pretty) {
                int j;
                qstring_append(str, "\n");
                for (j = 0; j < indent; j++)
                    qstring_append(str, "    ");
            }
            qstring_append(str, "]");
            break;
        }
        case QTYPE_QFLOAT: {
            QFloat *val = qobject_to_qfloat(obj);
            char buffer[1024];
            int len;

            len = snprintf(buffer, sizeof(buffer), "%f", qfloat_get_double(val));
            while (len > 0 && buffer[len - 1] == '0') {
                len--;
            }

            if (len && buffer[len - 1] == '.') {
                buffer[len - 1] = 0;
            } else {
                buffer[len] = 0;
            }

            qstring_append(str, buffer);
            break;
        }
        case QTYPE_QBOOL: {
            QBool *val = qobject_to_qbool(obj);

            if (qbool_get_int(val)) {
                qstring_append(str, "true");
            } else {
                qstring_append(str, "false");
            }
            break;
        }
        case QTYPE_QERROR:
        /* XXX: should QError be emitted? */
        case QTYPE_NONE:
            break;
    }
}

QString *qobject_to_json(const QObject *obj) {
    QString *str = qstring_new();

    to_json(obj, str, 0, 0);

    return str;
}

QString *qobject_to_json_pretty(const QObject *obj) {
    QString *str = qstring_new();

    to_json(obj, str, 1, 0);

    return str;
}
